RESUMO
Hepatitis C virus (HCV) is a small, single-stranded, positive-sense RNA virus that infects more than an estimated 70 million people worldwide. Untreated, persistent HCV infection often results in chronic hepatitis, cirrhosis, or liver failure, with progression to hepatocellular carcinoma. Current anti-HCV regimens comprising direct acting antivirals (DAAs) can provide curative treatment; however, due to high costs there remains a need for effective, shorter-duration, and affordable treatments. Recently, we disclosed anti-HCV activity of the cheap antihistamine chlorcyclizine, targeting viral entry. Following our hit-to-lead optimization campaign, we report evaluation of preclinical in vitro absorption, distribution, metabolism, and excretion properties, and in vivo pharmacokinetic profiles of lead compounds. This led to selection of a new lead compound and evaluation of efficacy in chimeric mice engrafted with primary human hepatocytes infected with HCV. Further development and incorporation of this compound into DAA regimens has the potential to improve treatment efficacy, affordability, and accessibility.
Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Hepatite C Crônica/tratamento farmacológico , Piperazinas/farmacologia , Animais , Carcinoma Hepatocelular/virologia , Linhagem Celular , Genótipo , Hepatócitos/virologia , Humanos , Cirrose Hepática/virologia , Neoplasias Hepáticas/virologia , Masculino , Camundongos , Camundongos SCID , Internalização do Vírus/efeitos dos fármacosRESUMO
Infection with human cytomegalovirus (HCMV) is a threat for pregnant women and immunocompromised hosts. Although limited drugs are available, development of new agents against HCMV is desired. Through screening of the LOPAC library, we identified emetine as HCMV inhibitor. Additional studies confirmed its anti-HCMV activities in human foreskin fibroblasts: EC50-40±1.72 nM, CC50-8±0.56 µM, and selectivity index of 200. HCMV inhibition occurred after virus entry, but before DNA replication, and resulted in decreased expression of viral proteins. Synergistic virus inhibition was achieved when emetine was combined with ganciclovir. In a mouse CMV (MCMV) model, emetine was well-tolerated, displayed long half-life, preferential distribution to tissues over plasma, and effectively suppressed MCMV. Since the in vitro anti-HCMV activity of emetine decreased significantly in low-density cells, a mechanism involving cell cycle regulation was suspected. HCMV inhibition by emetine depended on ribosomal processing S14 (RPS14) binding to MDM2, leading to disruption of HCMV-induced MDM2-p53 and MDM2-IE2 interactions. Irrespective of cell density, emetine induced RPS14 translocation into the nucleus during infection. In infected high-density cells, MDM2 was available for interaction with RPS14, resulting in disruption of MDM2-p53 interaction. However, in low-density cells the pre-existing interaction of MDM2-p53 could not be disrupted, and RPS14 could not interact with MDM2. In high-density cells the interaction of MDM2-RPS14 resulted in ubiquitination and degradation of RPS14, which was not observed in low-density cells. In infected-only or in non-infected emetine-treated cells, RPS14 failed to translocate into the nucleus, hence could not interact with MDM2, and was not ubiquitinated. HCMV replicated similarly in RPS14 knockdown or control cells, but emetine did not inhibit virus replication in the former cell line. The interaction of MDM2-p53 was maintained in infected RPS14 knockdown cells despite emetine treatment, confirming a unique mechanism by which emetine exploits RPS14 to disrupt MDM2-p53 interaction. Summarized, emetine may represent a promising candidate for HCMV therapy alone or in combination with ganciclovir through a novel host-dependent mechanism.
Assuntos
Antivirais/farmacologia , Infecções por Citomegalovirus , Citomegalovirus/efeitos dos fármacos , Emetina/farmacologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Modelos Animais de Doenças , Imunofluorescência , Humanos , Immunoblotting , Imunoprecipitação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal , Reação em Cadeia da Polimerase , Replicação Viral/efeitos dos fármacosRESUMO
Duchenne muscular dystrophy (DMD) is a fatal muscle disease caused by mutations in the dystrophin gene, resulting in a complete loss of the dystrophin protein. Dystrophin is a critical component of the dystrophin glycoprotein complex (DGC), which links laminin in the extracellular matrix to the actin cytoskeleton within myofibers and provides resistance to shear stresses during muscle activity. Loss of dystrophin in DMD patients results in a fragile sarcolemma prone to contraction-induced muscle damage. The α7ß1 integrin is a laminin receptor protein complex in skeletal and cardiac muscle and a major modifier of disease progression in DMD. In a muscle cell-based screen for α7 integrin transcriptional enhancers, we identified a small molecule, SU9516, that promoted increased α7ß1 integrin expression. Here we show that SU9516 leads to increased α7B integrin in murine C2C12 and human DMD patient myogenic cell lines. Oral administration of SU9516 in the mdx mouse model of DMD increased α7ß1 integrin in skeletal muscle, ameliorated pathology, and improved muscle function. We show that these improvements are mediated through SU9516 inhibitory actions on the p65-NF-κB pro-inflammatory and Ste20-related proline alanine rich kinase (SPAK)/OSR1 signaling pathways. This study identifies a first in-class α7 integrin-enhancing small-molecule compound with potential for the treatment of DMD.
Assuntos
Imidazóis/farmacologia , Indóis/farmacologia , Integrinas/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Modelos Animais de Doenças , Progressão da Doença , Feminino , Fibrose , Humanos , Integrinas/agonistas , Camundongos , Camundongos Endogâmicos mdx , Modelos Biológicos , Desenvolvimento Muscular/efeitos dos fármacos , Força Muscular , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/tratamento farmacológico , Mioblastos Esqueléticos/citologia , Mioblastos Esqueléticos/efeitos dos fármacos , Mioblastos Esqueléticos/metabolismo , NF-kappa B/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Regeneração/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
Multidrug resistance (MDR) is a major obstacle to the successful chemotherapy of cancer. MDR is often the result of overexpression of ATP-binding cassette transporters following chemotherapy. A common ATP-binding cassette transporter that is overexpressed in MDR cancer cells is P-glycoprotein, which actively effluxes drugs against a concentration gradient, producing an MDR phenotype. Collateral sensitivity (CS), a phenomenon of drug hypersensitivity, is defined as the ability of certain compounds to selectively target MDR cells, but not the drug-sensitive parent cells from which they were derived. The drug tiopronin has been previously shown to elicit CS. However, unlike other CS agents, the mechanism of action was not dependent on the expression of P-glycoprotein in MDR cells. We have determined that the CS activity of tiopronin is mediated by the generation of reactive oxygen species (ROS) and that CS can be reversed by a variety of ROS-scavenging compounds. Specifically, selective toxicity of tiopronin toward MDR cells is achieved by inhibition of glutathione peroxidase (GPx), and the mode of inhibition of GPx1 by tiopronin is shown in this report. Why MDR cells are particularly sensitive to ROS is discussed, as is the difficulty in exploiting this hypersensitivity to tiopronin in the clinic.
Assuntos
Inibidores Enzimáticos/farmacologia , Glutationa Peroxidase/antagonistas & inibidores , Tiopronina/farmacologia , Sequência de Aminoácidos , Sequência de Bases , Linhagem Celular Tumoral , Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Glutationa Peroxidase/química , Humanos , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Espécies Reativas de Oxigênio/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em Tandem , Tiomalatos/farmacologiaRESUMO
A high-throughput screening campaign was conducted to interrogate a 380,000+ small-molecule library for novel D2 dopamine receptor modulators using a calcium mobilization assay. Active agonist compounds from the primary screen were examined for orthogonal D2 dopamine receptor signaling activities including cAMP modulation and ß-arrestin recruitment. Although the majority of the subsequently confirmed hits activated all signaling pathways tested, several compounds showed a diminished ability to stimulate ß-arrestin recruitment. One such compound (MLS1547; 5-chloro-7-[(4-pyridin-2-ylpiperazin-1-yl)methyl]quinolin-8-ol) is a highly efficacious agonist at D2 receptor-mediated G protein-linked signaling, but does not recruit ß-arrestin as demonstrated using two different assays. This compound does, however, antagonize dopamine-stimulated ß-arrestin recruitment to the D2 receptor. In an effort to investigate the chemical scaffold of MLS1547 further, we characterized a set of 24 analogs of MLS1547 with respect to their ability to inhibit cAMP accumulation or stimulate ß-arrestin recruitment. A number of the analogs were similar to MLS1547 in that they displayed agonist activity for inhibiting cAMP accumulation, but did not stimulate ß-arrestin recruitment (i.e., they were highly biased). In contrast, other analogs displayed various degrees of G protein signaling bias. These results provided the basis to use pharmacophore modeling and molecular docking analyses to build a preliminary structure-activity relationship of the functionally selective properties of this series of compounds. In summary, we have identified and characterized a novel G protein-biased agonist of the D2 dopamine receptor and identified structural features that may contribute to its biased signaling properties.
Assuntos
Arrestinas/antagonistas & inibidores , Proteínas de Ligação ao GTP/metabolismo , Receptores de Dopamina D2/metabolismo , Animais , Arrestinas/metabolismo , Células CHO , Linhagem Celular , Cricetulus , AMP Cíclico/metabolismo , Células HEK293 , Humanos , Ligação Proteica/fisiologia , Transdução de Sinais/fisiologia , Bibliotecas de Moléculas Pequenas , Relação Estrutura-Atividade , beta-ArrestinasRESUMO
CONTEXT: Thyroid-stimulating hormone (or thyrotropin) receptor (TSHR) could be a selective target for small molecule ligands to treat thyroid cancer (TC). OBJECTIVE: We report a novel, orally efficacious ligand for TSHR that exhibits proliferation inhibitory activity against human TC in vitro and in vivo, and inhibition of metastasis in vivo. METHODS: A35 (NCATS-SM4420; NCGC00241808) was selected from a sublibrary of >200 TSHR ligands. Cell proliferation assays including BrdU incorporation and WST-1, along with molecular docking studies were done. In vivo activity of A35 was assessed in TC cell-derived xenograft (CDX) models with immunocompromised (NSG) mice. Formalin-fixed, paraffin-embedded sections of tumor and lung tissues were observed for the extent of cell death and metastasis. RESULTS: A35 was shown to stimulate cAMP production in some cell types by activating TSHR but not in TC cells, MDA-T32, and MDA-T85. A35 inhibited proliferation of MDA-T32 and MDA-T85 in vitro and in vivo, and pulmonary metastasis of MDA-T85F1 in mice. In vitro, A35 inhibition of proliferation was reduced by a selective TSHR antagonist. Inhibition of CDX tumor growth without decreases in mouse weights and liver function showed A35 to be efficacious without apparent toxicity. Lastly, A35 reduced levels of Ki67 in the tumors and metastatic markers in lung tissues. CONCLUSION: We conclude that A35 is a TSHR-selective inhibitor of TC cell proliferation and metastasis, and suggest that A35 may be a promising lead drug candidate for the treatment of differentiated TC in humans.
Assuntos
Proliferação de Células , Receptores da Tireotropina , Neoplasias da Glândula Tireoide , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Humanos , Camundongos , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/metabolismo , Proliferação de Células/efeitos dos fármacos , Receptores da Tireotropina/antagonistas & inibidores , Receptores da Tireotropina/metabolismo , Ligantes , Linhagem Celular Tumoral , Administração Oral , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/administração & dosagem , Metástase Neoplásica , Simulação de Acoplamento Molecular , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , FemininoRESUMO
The molecular mechanisms underlying seizure generation remain elusive, yet they are crucial for developing effective treatments for epilepsy. The current study shows that inhibiting c-Abl tyrosine kinase prevents apoptosis, reduces dendritic spine loss, and maintains N-methyl-d-aspartate (NMDA) receptor subunit 2B (NR2B) phosphorylated in in vitro models of excitotoxicity. Pilocarpine-induced status epilepticus (SE) in mice promotes c-Abl phosphorylation, and disrupting c-Abl activity leads to fewer seizures, increases latency toward SE, and improved animal survival. Currently, clinically used c-Abl inhibitors are non-selective and have poor brain penetration. The allosteric c-Abl inhibitor, neurotinib, used here has favorable potency, selectivity, pharmacokinetics, and vastly improved brain penetration. Neurotinib-administered mice have fewer seizures and improved survival following pilocarpine-SE induction. Our findings reveal c-Abl kinase activation as a key factor in ictogenesis and highlight the impact of its inhibition in preventing the insurgence of epileptic-like seizures in rodents and humans.
Assuntos
Pilocarpina , Proteínas Proto-Oncogênicas c-abl , Convulsões , Animais , Masculino , Camundongos , Apoptose/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Neurônios/patologia , Neurônios/metabolismo , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/metabolismo , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Convulsões/induzido quimicamente , Convulsões/tratamento farmacológico , Convulsões/patologia , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/tratamento farmacológico , Estado Epiléptico/patologiaRESUMO
Background: Growing evidence suggests that the non-receptor tyrosine kinase, c-Abl, plays a significant role in the pathogenesis of Alzheimer's disease (AD). Here, we analyzed the effect of c-Abl on the cognitive performance decline of APPSwe/PSEN1ΔE9 (APP/PS1) mouse model for AD. Methods: We used the conditional genetic ablation of c-Abl in the brain (c-Abl-KO) and pharmacological treatment with neurotinib, a novel allosteric c-Abl inhibitor with high brain penetrance, imbued in rodent's chow. Results: We found that APP/PS1/c-Abl-KO mice and APP/PS1 neurotinib-fed mice had improved performance in hippocampus-dependent tasks. In the object location and Barnes-maze tests, they recognized the displaced object and learned the location of the escape hole faster than APP/PS1 mice. Also, APP/PS1 neurotinib-fed mice required fewer trials to reach the learning criterion in the memory flexibility test. Accordingly, c-Abl absence and inhibition caused fewer amyloid plaques, reduced astrogliosis, and preserved neurons in the hippocampus. Discussion: Our results further validate c-Abl as a target for AD, and the neurotinib, a novel c-Abl inhibitor, as a suitable preclinical candidate for AD therapies.
RESUMO
The endoplasmic reticulum is a subcellular organelle key in the control of synthesis, folding, and sorting of proteins. Under endoplasmic reticulum stress, an adaptative unfolded protein response is activated; however, if this activation is prolonged, cells can undergo cell death, in part due to oxidative stress and mitochondrial fragmentation. Here, we report that endoplasmic reticulum stress activates c-Abl tyrosine kinase, inducing its translocation to mitochondria. We found that endoplasmic reticulum stress-activated c-Abl interacts with and phosphorylates the mitochondrial fusion protein MFN2, resulting in mitochondrial fragmentation and apoptosis. Moreover, the pharmacological or genetic inhibition of c-Abl prevents MFN2 phosphorylation, mitochondrial fragmentation, and apoptosis in cells under endoplasmic reticulum stress. Finally, in the amyotrophic lateral sclerosis mouse model, where endoplasmic reticulum and oxidative stress has been linked to neuronal cell death, we demonstrated that the administration of c-Abl inhibitor neurotinib delays the onset of symptoms. Our results uncovered a function of c-Abl in the crosstalk between endoplasmic reticulum stress and mitochondrial dynamics via MFN2 phosphorylation.
RESUMO
We have developed and characterized a novel D2R antagonist with exceptional GPCR selectivity - ML321. In functional profiling screens of 168 different GPCRs, ML321 showed little activity beyond potent inhibition of the D2R and to a lesser extent the D3R, demonstrating excellent receptor selectivity. The D2R selectivity of ML321 may be related to the fact that, unlike other monoaminergic ligands, ML321 lacks a positively charged amine group and adopts a unique binding pose within the orthosteric binding site of the D2R. PET imaging studies in non-human primates demonstrated that ML321 penetrates the CNS and occupies the D2R in a dose-dependent manner. Behavioral paradigms in rats demonstrate that ML321 can selectively antagonize a D2R-mediated response (hypothermia) while not affecting a D3R-mediated response (yawning) using the same dose of drug, thus indicating exceptional in vivo selectivity. We also investigated the effects of ML321 in animal models that are predictive of antipsychotic efficacy in humans. We found that ML321 attenuates both amphetamine- and phencyclidine-induced locomotor activity and restored pre-pulse inhibition (PPI) of acoustic startle in a dose-dependent manner. Surprisingly, using doses that were maximally effective in both the locomotor and PPI studies, ML321 was relatively ineffective in promoting catalepsy. Kinetic studies revealed that ML321 exhibits slow-on and fast-off receptor binding rates, similar to those observed with atypical antipsychotics with reduced extrapyramidal side effects. Taken together, these observations suggest that ML321, or a derivative thereof, may exhibit â³atypicalâ³ antipsychotic activity in humans with significantly fewer side effects than observed with the currently FDA-approved D2R antagonists.
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In recent years, sugars with a unique chemical handle have been used to detect and elucidate the function of glycoconjugates. Such chemical handles have generally been part of an N-acetyl moiety of a sugar. We have previously developed several applications using the single mutant Y289L-ß1,4-galactosyltransferase I (Y289L-ß4Gal-T1) and the wild-type polypeptide-α-GalNAc-T enzymes with UDP-C2-keto-Gal. Here, we describe for the first time that the GlcNAc-transferring enzymes-R228K-Y289L-ß4Gal-T1 mutant enzyme, the wild-type human ß1,3-N-acetylglucosaminyltransferase-2 and human Maniac Fringe-can also transfer the GlcNAc analog C2-keto-Glc molecule from UDP-C2-keto-Glc to their respective acceptor substrates. Although the R228K-Y289L-ß4Gal-T1 mutant enzyme transfers the donor sugar substrate GlcNAc or its analog C2-keto-Glc only to its natural acceptor substrate, GlcNAc, it does not transfer to its analog C2-keto-Glc. Thus, these observations suggest that the GlcNAc-transferring glycosyltransferases can generally accommodate a chemical handle in the N-acetyl-binding cavity of the donor sugar substrate, but not in the N-acetyl-binding cavity of the acceptor sugar.
Assuntos
Galactose/análogos & derivados , Galactose/química , Hexosiltransferases/química , Peptídeos e Proteínas de Sinalização Intracelular/química , Proteínas de Membrana/química , N-Acetilglucosaminiltransferases/química , Acetilglucosamina/química , Substituição de Aminoácidos , Sítios de Ligação , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia de Afinidade , Clonagem Molecular , Escherichia coli , Fator VII/química , Glucosiltransferases , Glicosilação , Hexosiltransferases/biossíntese , Hexosiltransferases/genética , Hexosiltransferases/isolamento & purificação , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/isolamento & purificação , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Proteínas de Membrana/isolamento & purificação , Modelos Moleculares , Dados de Sequência Molecular , Proteínas Mutantes/química , N-Acetilglucosaminiltransferases/biossíntese , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/isolamento & purificação , Oligossacarídeos/química , Ligação Proteica , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação , Propriedades de SuperfícieRESUMO
Niemann-Pick type A (NPA) disease is a fatal lysosomal neurodegenerative disorder caused by the deficiency in acid sphingomyelinase (ASM) activity. NPA patients present severe and progressive neurodegeneration starting at an early age. Currently, there is no effective treatment for this disease and NPA patients die between 2 and 3 years of age. NPA is characterized by an accumulation of sphingomyelin in lysosomes and dysfunction in the autophagy-lysosomal pathway. Recent studies show that c-Abl tyrosine kinase activity downregulates autophagy and the lysosomal pathway. Interestingly, this kinase is also activated in other lysosomal neurodegenerative disorders. Here, we describe that c-Abl activation contributes to the mechanisms of neuronal damage and death in NPA disease. Our data demonstrate that: 1) c-Abl is activated in-vitro as well as in-vivo NPA models; 2) imatinib, a clinical c-Abl inhibitor, reduces autophagy-lysosomal pathway alterations, restores autophagy flux, and lowers sphingomyelin accumulation in NPA patient fibroblasts and NPA neuronal models and 3) chronic treatment with nilotinib and neurotinib, two c-Abl inhibitors with differences in blood-brain barrier penetrance and target binding mode, show further benefits. While nilotinib treatment reduces neuronal death in the cerebellum and improves locomotor functions, neurotinib decreases glial activation, neuronal disorganization, and loss in hippocampus and cortex, as well as the cognitive decline of NPA mice. Our results support the participation of c-Abl signaling in NPA neurodegeneration and autophagy-lysosomal alterations, supporting the potential use of c-Abl inhibitors for the clinical treatment of NPA patients.
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Many natural biomacromolecules are homochiral and are built from constituents possessing identical handedness. The construction of synthetic molecules, macromolecules, and supramolecular structures with tailored stereochemical sequences can detail the relationship between chirality and function and provide insight into the process that leads to the selection of handedness and amplification of chirality. Dendritic dipeptides, previously reported from our laboratory, self-assemble into helical porous columns and serve as fundamental mimics of natural porous helix-forming proteins and supramolecular polymers. Herein, the synthesis of all stereochemical permutations of a self-assembling dendritic dipeptide including homochiral, heterochiral, and differentially racemized variants is reported. A combination of CD/UV-vis spectroscopy in solution and in film, X-ray diffraction, and differential scanning calorimetry studies in solid state established the role of the stereochemistry of the dipeptide on the thermodynamics and mechanism of self-assembly. It was found that the highest degree of stereochemical purity, enantiopure homochiral dendritic dipeptides, exhibits the most thermodynamically favorable self-assembly process in solution corresponding to the greatest degree of helical order and intracolumnar crystallization in solid state. Reducing the stereochemical purity of the dendritic dipeptide through heterochirality or by partially or fully racemizing the dendritic dipeptide destructively interferes with the self-assembly process. All dendritic dipeptides were shown to coassemble into single columns regardless of their stereochemistry. Because these columns exhibit no deracemization, the thermodynamic advantage of enantiopurity and homochirality suggests a mechanism for stereochemical selection and chiral amplification.
Assuntos
Dendrímeros/síntese química , Dipeptídeos/síntese química , Cristalografia por Raios X , Dendrímeros/química , Dipeptídeos/química , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Modelos Moleculares , Conformação Proteica , EstereoisomerismoRESUMO
The potential of wild-type and mutant glycosyltransferases to produce glycoconjugates carrying sugar moieties with chemical handles has made it possible to conjugate biomolecules with orthogonal reacting groups at specific sites. The synthesis of UDP-2-(2-ketopropyl)galactose has been previously carried out, albeit with difficulty and low efficiency. A modified approach has been developed for the synthesis of UDP-2-(2-ketopropyl)glucose and UDP-2-(2-ketopropyl)galactose, allowing better access to the desired test compounds, the UDP-2-(2-ketopropyl)glucose and UDP-2-(2-ketopropyl)galactose analogs were synthesized in 8 steps and 4.8% and 5.3% overall yield respectively, an improvement over the 1(st) generation synthesis involving 8 steps and an overall yield of 0.7%.
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A large number of synthetic and natural compounds self-organize into bulk phases exhibiting periodicities on the 10(-8)-10(-6) metre scale as a consequence of their molecular shape, degree of amphiphilic character and, often, the presence of additional non-covalent interactions. Such phases are found in lyotropic systems (for example, lipid-water, soap-water), in a range of block copolymers and in thermotropic (solvent-free) liquid crystals. The resulting periodicity can be one-dimensional (lamellar phases), two-dimensional (columnar phases) or three dimensional ('micellar' or 'bicontinuous' phases). All such two- and three-dimensional structures identified to date obey the rules of crystallography and their symmetry can be described, respectively, by one of the 17 plane groups or 230 space groups. The 'micellar' phases have crystallographic counterparts in transition-metal alloys, where just one metal atom is equivalent to a 10(3)-10(4)-atom micelle. However, some metal alloys are known to defy the rules of crystallography and form so-called quasicrystals, which have rotational symmetry other than the allowed two-, three-, four- or six-fold symmetry. Here we show that such quasiperiodic structures can also exist in the scaled-up micellar phases, representing a new mode of organization in soft matter.
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Natural pore-forming proteins act as viral helical coats and transmembrane channels, exhibit antibacterial activity and are used in synthetic systems, such as for reversible encapsulation or stochastic sensing. These diverse functions are intimately linked to protein structure. The close link between protein structure and protein function makes the design of synthetic mimics a formidable challenge, given that structure formation needs to be carefully controlled on all hierarchy levels, in solution and in the bulk. In fact, with few exceptions, synthetic pore structures capable of assembling into periodically ordered assemblies that are stable in solution and in the solid state have not yet been realized. In the case of dendrimers, covalent and non-covalent coating and assembly of a range of different structures has only yielded closed columns. Here we describe a library of amphiphilic dendritic dipeptides that self-assemble in solution and in bulk through a complex recognition process into helical pores. We find that the molecular recognition and self-assembly process is sufficiently robust to tolerate a range of modifications to the amphiphile structure, while preliminary proton transport measurements establish that the pores are functional. We expect that this class of self-assembling dendrimers will allow the design of a variety of biologically inspired systems with functional properties arising from their porous structure.
Assuntos
Biopolímeros/química , Biopolímeros/metabolismo , Dipeptídeos/química , Dipeptídeos/metabolismo , Transporte Biológico , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica , Modelos Moleculares , Porosidade , Estrutura Quaternária de Proteína , Prótons , EstereoisomerismoRESUMO
Th17 cells are critical drivers of autoimmune diseases and immunopathology. There is an unmet need to develop therapies targeting pathogenic Th17 cells for the treatment of autoimmune disorders. Here, we report that anxiolytic FGIN-1-27 inhibits differentiation and pathogenicity of Th17 cells in vitro and in vivo using the experimental autoimmune encephalomyelitis (EAE) model of Th17 cell-driven pathology. Remarkably, we found that the effects of FGIN-1-27 were independent of translocator protein (TSPO), the reported target for this small molecule, and instead were driven by a metabolic switch in Th17 cells that led to the induction of the amino acid starvation response and altered cellular fatty acid composition. Our findings suggest that the small molecule FGIN-1-27 can be re-purposed to relieve autoimmunity by metabolic reprogramming of pathogenic Th17 cells.
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Ansiolíticos/farmacologia , Autoimunidade/efeitos dos fármacos , Técnicas de Reprogramação Celular , Encefalomielite Autoimune Experimental , Ácidos Indolacéticos/farmacologia , Células Th17/imunologia , Animais , Encefalomielite Autoimune Experimental/imunologia , Encefalomielite Autoimune Experimental/patologia , Encefalomielite Autoimune Experimental/terapia , Camundongos , Camundongos Transgênicos , Receptores de GABA/imunologia , Células Th17/patologiaRESUMO
Fluoxazolevir is an aryloxazole-based entry inhibitor of hepatitis C virus (HCV). We show that fluoxazolevir inhibits fusion of HCV with hepatic cells by binding HCV envelope protein 1 to prevent fusion. Nine of ten fluoxazolevir resistance-associated substitutions are in envelope protein 1, and four are in a putative fusion peptide. Pharmacokinetic studies in mice, rats and dogs revealed that fluoxazolevir localizes to the liver. A 4-week intraperitoneal regimen of fluoxazolevir in humanized chimeric mice infected with HCV genotypes 1b, 2a or 3 resulted in a 2-log reduction in viraemia, without evidence of drug resistance. In comparison, daclatasvir, an approved HCV drug, suppressed more than 3 log of viraemia but is associated with the emergence of resistance-associated substitutions in mice. Combination therapy using fluoxazolevir and daclatasvir cleared HCV genotypes 1b and 3 in mice. Fluoxazolevir combined with glecaprevir and pibrentasvir was also effective in clearing multidrug-resistant HCV replication in mice. Fluoxazolevir may be promising as the next generation of combination drug cocktails for HCV treatment.
Assuntos
Antivirais/administração & dosagem , Hepacivirus/efeitos dos fármacos , Hepatite C/tratamento farmacológico , Internalização do Vírus/efeitos dos fármacos , Animais , Carbamatos/administração & dosagem , Modelos Animais de Doenças , Cães , Quimioterapia Combinada , Genótipo , Hepacivirus/classificação , Hepacivirus/genética , Hepacivirus/fisiologia , Hepatite C/virologia , Humanos , Imidazóis/administração & dosagem , Masculino , Camundongos , Pirrolidinas/administração & dosagem , Ratos , Ratos Sprague-Dawley , Valina/administração & dosagem , Valina/análogos & derivados , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/metabolismoRESUMO
The synthesis of a library containing 12 conical dendrons that self-assemble into hollow spherical supramolecular dendrimers is reported. The design principles for this library were accessed by development of a method that allows the identification of hollow spheres, followed by structural and retrostructural analysis of their Pm3n cubic lattice. The first hollow spherical supramolecular dendrimer was made by replacing the tapered dendron, from the previously reported tapered dendritic dipeptide that self-assembled into helical pores, with its constitutional isomeric conical dendron. This strategy generated a conical dendritic dipeptide that self-assembled into a hollow spherical supramolecular dendrimer that self-organizes in a Pm3n cubic lattice. Other examples of hollow spheres were assembled from conical dendrons without a dipeptide at their apex. These are conical dendrons originated from tapered dendrons containing additional benzyl ether groups at their apex. The inner part of the hollow sphere assembled from the dipeptide resembles the path of a spherical helix or loxodrome and, therefore, is chiral. The spheres assembled from other conical dendrons are nonhelical, even when they contain stereocenters on the alkyl groups from their periphery. Functionalization of the apex of the conical dendrons with diethylene glycol allowed the encapsulation of LiOTf and RbOTf in the center of the hollow sphere. These experiments showed that hollow spheres function as supramolecular dendritic capsules and therefore are expected to display functions complementary to those of other related molecular and supramolecular structures.